Laser ignition assisted spark-induced breakdown spectroscopy for the ultra-sensitive detection of trace mercury ions in aqueous solutions

The trace mercury ions in aqueous solutions were electrically deposited on the surface of a high purity copper plate and then quantitatively analyzed by laser ignition assisted spark-induced breakdown spectroscopy (LI-SIBS). Laser ignition is helpful to enhance discharge stability and reduce the required voltage level in SIBS. The analysis sensitivity of mercury in LI-SIBS was enhanced by a factor of 30 in comparison with that in laser-induced breakdown spectroscopy (LIBS). A 6% relative standard deviation has been achieved in multiple measurements and the limit of detection of mercury in aqueous solutions by LI-SIBS has reached to 2 mu gL(-1) under present experimental conditions. LI-SIBS overcomes the low-sensitivity shortcoming of LIBS on the analysis of mercury. By combining with electrical deposition enrichment, LI-SIBS provides a simple and ultra-sensitive analysis method for mercury ions in water.